Driving mechanism.



C. T. HENDERSON.

DRIVING MECHANISM.

APPLICATION FILED JUNE 1, I914.

1,270,028. Patented June 18, 1918.

UNITED STATES PATENT OFFICE.

CLARK T. HENDERSON, F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER- HAMMER MFG. (70., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONSIN.

DRIVING MECHANISM.

Specification of Letters Intent.

Application filed June 1, 1914. Serial No. 842,186.

trolling means for driven apparatus.

()ne of the objects of the invention is to provide improved means for eflecting the drive of a member at predetermined successive speeds irrespective of variations in the load of such member.

A further object is to provide driving and controlling means for such purpose wherein the speed variations of the driven member automatically occur at predetermined periods andwithout waste of power.

A's-exemplary of apparatus to which'this invention is especially applicable, skip hoisting machinery may be mentioned. In devices of such character the skip car is designed to be driven at relatively high speed during the major portion of its hoist and to be slowed to a predetermined reduced speed when the car approaches dumping position. In practice,.however, the successive loads of the car vary materially in weight and difiiculty has heretofore been encountered in establishin and maintaining the desired predetermine speed rates during all operations of the hoist.

The accompanying drawing shows a typical embodiment of the invention as applied to a skip hoist.

In the drawing, Figure 1 is a schematic view of a driving mechanism and driven skip cars;

Fig. 2 is a sectional view of the driving gears; and,

1 Fig. 3 is a diagram of circuit connections for the driving motors.

The medium for transmitting power from the driving sources to the driven member comprises a gear train A. A large motor B and a small motor G constitute the power supply for the mechanism and. a driven member D is provided for operative connection with a driven apparatus, for example, a skip hoist drum E.

6 The gearing A includes a shaft 1 having thereon a fixed pinion 2 in constant mesh with a driving pinion 3 of the small driving motor C. The shaft 1 is also provided with a fixed pinion 1 in constant mesh with a pair of epicyclic gears 5 loosely journaled on ofiset studs 6 of a driven sleeve 7. The shaft 1 is alined with the sleeve 7 and is preferably journaled therethrough. A casing 8 incloses the pinion 1 and gears 5 and is provided with bearings 9 and 10 on the shaft 1 and sleeve 7 respectively. The circumference of the casing is toothed internally to provide a gear 11 in mesh with the gears 5 and is also toothed externally to provide a gear 12 in mesh with a pinion 13 keyed to the armatureshaft of the large driving motor B. The driven member D, as

illustrated, comprises a gear 14 keyed to the driven, sleeve 7 and meshing with a pinion 15 connected by the shaft 16 to suitable means such as a drum 17, which operates the skip cars 18 and 19. The driving pinions 3 and 13 are preferably fixed to the armature shafts 20 and 21 of the small and large motors respectively. Each of the pinions, moreover, is adapted to be braked by electro-responsive braking devices 22 and 23 respectively connected with the armature shafts of the motors. These braking devices are releasable by means of suitable windings, when their respective motors are in operation, as will hereinafter appear.

Briefly considered, the hoisting apparatus E comprises skip cars 18 and 19 adapted to be alternately raised to dumping position and lowered to filling position by a cable 24 over the drum l7. It'is desirable that the skip cars when filled travel at high speed from initial position to a point ad- 'acent dumping position.

owever, that the speed of the car be reduced to a definite rate as its limit of travel is approached before dumping position is attained. Furthermore, it is desirable that the skip cars travel during successive operations at the same predetermined speeds 1rres ective of initial variations in the load weight thereof.

Adverting to the driving mechanism, the operation thereof is as follows: Assumin that a skip car is ready to be hoisted, b0 motors B and C are set in operation in the same direction. As above mentioned, the motor B is of materially greater power than the motor C. Both motors, however, are de- It is necessary,

signed to operate at constant speeds in such ratio that, when running, the R. P. of the'shaft 1 and the R. P. M. of the casing 8 shall be equal. When the two motors are thus started the epicyclic gears 5 are bodily turned about the shaft 1 and carry the driven sleeve 7 at the same speed as the shaft 1 and casing 8. Power is then transmitted by the gears 14;, 15, shaft 16 and drum 17 to the hoisting apparatus and the skip car is raised at a vdefinite high speed by the combined power of the two motors B and C. As the car approaches dumping position the motor B is designed to be stopped, and the pinion 13 simultaneously braked by the device 23, thus locking the casing 8 against rotation. The small motor C, however, continues to drive the sleeve 7 and driven gear it but at a reduced speed through the medium of the pinion 4, the gears 5, and the now stationary casing 8. The skip car is accordingly moved through the latter part of its travel at a predetermined slow speed. Finally, when the car assumes dumping position the small motor C is also designed to be stopped and the drive accordingly interrupted. A reverse operation of the motors B and C effects a reversal in the direction of movement of the driving medium and the driven parts, as will be apparent.

In, practice, the motors B and C and the braking devices 23 and 22 are automatically controlled in accordance with the position of the skip cars. It is obvious, however, that the two motors may be independently and manually controlled, if desired. Fig. 3 of the drawing represents one wiring connection for the motors and braking devices. As there shown the armatures of the motors B and O are connected in parallel and the respective branches thereof controlled by independent electro responsive switches 25 and 25 Commonstarting resistance R is interposed in the armature circuits. Field windings 26 and 26 of the motors are permanently connected across the lines from conductor 27 in parallel through conductors 28 and 29 to the opposite line 30. Two pairs of limit switches 31, 31 and 32, 32 are provided to be actuated by the skip cars, and the switches of each pair are designed to be successively opened by the rising skip car to interrupt circuit to the armature branches of the smalland large'motors and simultaneously release the. braking devices therefor. A controlling switch S is provided to govern the starting of the motors for alternately raising the skip cars.

Assuming that the, car 19 is to be lifted from lowermost position, the switch S is thrown, for example, in a clockwise direction. At this time the other car 18 is in elevated position and the limit switches 32 and 32 have been opened thereby. The motor switches 25 and 25", however, are now closed by energization of windings 33 and 33. The circuit for the winding 33 of switch 25 may be traced from line 27 by conductor 34, in parallel through the coil 35 for the braking device 23 and the switch winding 33, by conductor 36 through the switch 31, along conductor 37 through the switch S to the opposite line 30. Circuit of the winding 33 of the switch 25 may be similarly traced from line 27 by conductor 34:, through the brake coil 35 and winding 33 in parallel, by conductor 36 through limit switch 31 to conductor 37 and thence to the other line 30, as described. The armature circuits are thus established from'line 27 through switch S to conductor 40, thence through resistance R, and, in parallel by conductors 41 and 41 to the motors, along conductor 42 and through the other side of switch S to the opposite line 30. Suitable switches 39, may, course, be provided for gradually removing the starting resistance R from the armature circuit. Both motors are thus simultaneousl set in operation and the driven mem er is accordingly moved by their combined power so that the skip car 19 is raised at high speed. As the car, however, approaches dumping position the same opens limit switch 31. Circuit through the winding 33 is thereupon inter- .rupted, the switch 25 accordingly opens, and

the large motor B is stopped. The braking device 23 is simultaneously released by deenergization of the winding 35 so that the casing 8 is stopped and held fixed. The drive of the sleeve 7 and the drum 17 is then continued by the small motor C at a definitely reduced speed dependent upon the ratio of the gear train A which may be practically any ratio desired. This predetermined second speed, moreover, is established without driving interruption or shock. As

the skip car 19 is further raised the limit switch 31 is opened and the winding 33 deenergized so that the switch 25 of the small motor armature circuit opens and the motor 0 is stopped. The braking device 22 is simultaneously rendered effective by deenergization of the brake coil 35". Both motors are now at rest and the driven member braked by the braking of the respective driving shafts. This condition is maintained until the switch S is moved to opposite position. The armature circuits of the two motors are then closed in the opposite direction between the lines and the movement of the driven parts is reversed, as will be apparent. The switches 25 and 25 in small motor through the reducing gearing,

When the c'ar18 dumps, the limit switch 32 is opened and the armature circuit of the small motor accordingly interrupted. The driven member 14 consequently again comes to rest and is maintained braked until the next cycle of operation.

As above mentioned, the large and small motors are both designed to operate at constant speeds, and the speed regulation of the skip cars is accomplished and overned without regulation of the motors 0t er than the starting and stopping thereof. Moreover, as both motors are operating only while the power thereof is required, no waste of energy can occur; and, as the transition from one speed to another is established through the epicyclic gears 5, the operation of the cars is rendered-smooth and constant. The speed of the skip cars on successive operatlons is also 'ent1rely independent of ordinary variations in the initial load thereof, and consequently rising skip cars always approach dumpin position at the same uniform speed and are rought to rest without liability of overrunningor bumping or variation in the stopping position.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with a variable load mechanism to be driven, of a plurality of driving motors therefor of different oapacities, the motor of lesser capacity being of a constant speed type and a planetary gear operatively connecting said mechanism and said motors, said gear being operable by said motors jointly withits gear parts in a fixed relation for high s ed drive of said mechanism and alsoopera 1e by said motor of lesser capacity, with the motor of greater capacity inert, for slow speed drive of said mechanism, whereby stopping of the latter motor and continued operation of the former motor provides for reduction of the speed of said mechanism to a substantially uniform value under varying load conditions. s

2. The combination with a variable load mechanism-to be driven, of a plurality of driving motors therefor of different capacities, the motor of lesser capacity being of a constant speed type a planetary gear operatively connecting said mechanism and said motors, said gear being operable by said motors jointly with its gear parts in a fixed relation for high speed drive of said mechanism and also operable by said motor of lesser capacity, with the motor of larger capacity inert, for slow speed drive of saidmechanism and limit means for said mechanism providing for arrest of the motor of larger capacity to reduce the speed of said mechanism to a substantially uniform value under varying load conditions and for subsequent arrest of said small motor to arrest said mechanism. I

3. The combination with a variable load mechanism' to be driven, a planetary gear having its planet gear member connected thereto, a relatively small driving motorfor the central gear member of said planetary ear and a relatively large driving motor or the remainin gear member of said planetary gear, sai last two mentioned gear members being operable at full speed of their respective motors to drive said mecha nism by non-planetary operation of said planet gear member and said second mentioned gear member being operable by its respective motor, with said third mentloned gear member stationary, to drive said mechanism by a planetary operation of said planet gear member. a

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

CLARK T. HENDERSON.

Witnesses:

L. A. WATSON, Tram RAM. 

